The Bosch iBooster is an electromechanical brake booster (rather than vacuum assisted) primarily found on Electric Vehicles such as Tesla, but can also be found on other vehicles including ones with an Internal Combustion Engine.

The iBooster is able to run in a fail-safe standalone mode with no other connections or communication to additional components needed besides voltage supply and chassis ground as the iBooster has an internal Pedal Travel Sensor that is externally wired to the iBooster ECU. The information from the Pedal Travel Sensor is used by the iBooster ECU to drive the electric motor which provides additional force towards the Master Cylinder.

Therefore the iBooster is an ideal component for many applications such as electric vehicle conversions (rather than using a vacuum pump), classic cars / muscle cars / hot rods (typically with manual brakes), limited vacuum pressure (such as diesel or turbo engines), or clearance issues of engine swaps (like the BMW E30 with a S54 engine).